SAN’A, Yemen — Security forces and supporters of a slain rebel preacher were involved in clashes yesterday in a renewal of violence that has claimed at least 33 lives.

As troops sealed off villages in Sa’dah province near the border with Saudi Arabia, clashes for the first time extended southward to the region of Arran, about 50 miles north of San’a, the capital, where fighters ambushed an army convoy, killing three soldiers, tribal sources said. The sources could not confirm casualties among the rebels.

Troops cordoned off villages in Sa’dah province on the lookout for followers of radical rebel Zaidi preacher Sheik Hussein Badr Eddin al-Huthi, who was killed by Yemeni troops Sept. 10.

Sheik al-Huthi was a radical preacher of the Zaidi sect, a moderate Shi’ite Muslim group dominant in northwestern Yemen but a minority in the rest of the mainly Sunni Muslim country. Yemeni President Ali Abdullah Saleh is a Zaidi.

Twenty-three rebels and 10 members of the army and security forces have been killed since Monday in the most serious confrontations since Sheik al-Huthi was declared dead, tribal sources told Agence France-Presse. The sources said authorities had detained 51 rebel fighters.

Officials had not confirmed the casualties or arrests.

In Riyadh, the Saudi Interior Ministry announced Monday that Saudi and Yemeni authorities had exchanged nearly three dozen suspects wanted for security-related matters.

Saudi authorities turned over eight Yemenis captured in Saudi Arabia, the ministry said in a statement carried by the official Saudi Press Agency. Twenty-five Saudis also wanted for security-related matters were handed to Saudi Arabia, the ministry said.

Early yesterday, gunfire and artillery could be heard from the northwestern mountains, where soldiers backed by tanks and armored vehicles cordoned off villages where rebels were suspected to be holed up.

Soldiers sealed the villages of Kutaf, Dahyan and Nushur in Sa’dah province, the tribal sources said.

On March 19, three prominent members of Sheik al-Huthi’s Faithful Youth movement were killed and two others wounded by police, who sustained three wounded in the first clash since authorities announced Sheik al-Huthi’s death. The latter’s three-month armed revolt in mountainous Sa’dah province near the Saudi border was crushed by a military offensive that left more than 400 people dead.

Authorities accused the fiery preacher of fomenting sectarian strife, but he had claimed he was targeted because of his opposition to the United States and its growing influence in the region.

Yemeni security forces said the renewed clashes were led by the slain preacher’s father, Badr Eddin al-Huthi, after he “launched treacherous and cowardly attacks” on several security outposts in the province. But tribal sources said the violence began with an attempt by security forces to strip al-Huthi followers of their heavy weapons.